Azathioprine is used to control severe active RA, usually as an ‘add on’ treatment to supplement the main DMARD or to enable the reduction of regular steroid treatment.  


Azathioprine is used to control severe active rheumatoid arthritis, usually as an ‘add on’ treatment to supplement the main disease modifying drug (DMARD) or to enable the reduction of regular steroid treatment.  

Azathioprine is now only used rarely since the continuing development of more effective targeted treatments 

Azathioprine is also used to minimise the possibility of rejection of transplanted organs as well as for other inflammatory conditions.  

Azathioprine damps down the immune system by slowing the rate of cell division amongst the inflammatory cells.  


Azathioprine has been widely prescribed since the 1960s. The benefit of treatment with azathioprine can take weeks or months to be established.  

Most commonly reported side effects  

As with any medication, azathioprine has a number of possible side effects, although it is important to remember that these are only potential side effects and they may not occur at all.  

Close monitoring of weekly blood tests for the first 8 weeks (or as advised) of treatment is very important.  

Side effects may include: nausea, vomiting, diarrhoea, throat ulcers, fever, infections, bruising and bleeding but this is not exhaustive.  

More information on side effects can be found in the patient information leaflet for azathioprine that comes with your medicine.  

Remember to report any concerns about possible side effects to your doctor, pharmacist or nurse.  

Azathioprine with other medicines  

There are some significant potential drug interactions between azathioprine and many other medicines. It is particularly important that a full and complete medical history is given to the prescribing doctor.  

Remember to take care when using any other medicines or complementary therapies (even if ‘bought over the counter’ for colds, flu or other home remedies). Remember to check with a doctor, pharmacist or nurse that they are safe to take with azathioprine as well as with any other medication taken.  

Azathioprine during pregnancy and breast-feeding  

Azathioprine must not be used during pregnancy without careful assessment of the risks and benefits. Breast-feeding is definitely not recommended whilst on treatment with azathioprine.  

Contraception must be used by both men and women during treatment with azathioprine and for three months after treatment has stopped.  

Azathioprine and immunization/vaccination  

Live vaccines (measles, mumps, rubella (MMR), chickenpox, oral polio (NOT injectable polio), BCG, oral typhoid and yellow fever) cannot be given to anyone already taking azathioprine.  

The possible response to killed vaccines (any vaccine that is not ‘Live’) is likely to be diminished because of azathioprine treatment and this results in a reduction of the protection that the vaccination provides.  

The annual flu vaccination and ‘pneumovax’ protection against pneumonia is permitted. If possible the ‘pneumovax’ vaccination should be given before starting azathioprine.  


Your prescriptions for medication will be free to you if you live in Northern Ireland, Scotland or Wales. In England, however, you may have to pay unless you have an exemption. Any medication that is administered in a hospital, an NHS walk-in centre or by your GP in person (such as injections into a joint) you will not be charged for. But you will have to pay for regular prescriptions unless you are under 16 or over 60, are on one of a number of benefits or have a specific exemption. Your GP or pharmacist will be able to advise you whether you have to pay or not.  

If you do have to pay and have to get more than 12 prescribed items in a year, you can save money by getting a Pre-Payment Certificate. They currently cost £104, and you can pay in monthly instalments. Visit or talk to your GP or pharmacist for more information.  

You will most likely be in receipt of one or more repeat prescriptions. Talk to your hospital healthcare team and/or your GP practice to find out how the system works in your area. Don’t assume that prescriptions will automatically be renewed.  

Your GP practice may also have links with local pharmacies, who will collect the prescriptions for you and make them up.  

It’s worth getting to know your pharmacist, whether they are based in your local health centre or hospital or on the high street. Some healthcare teams include a pharmacist with specialist knowledge of RA prescribing (ask your Rheumatology specialist nurse if that’s true in your case). Pharmacists are a valuable source of support and information. He or she can help if you are concerned about your medications or the instructions about your treatment, or if you need to check whether you can take other medications or over-the-counter treatments at the same time.  

You can also book an annual ‘Medicines Use Review’ with your pharmacist if, for example, you are taking multiple drugs, including, perhaps, drugs for a condition other than RA.  

Medicines in rheumatoid arthritis

We believe it is essential that people living with RA understand why certain medicines are used, when they are used and how they work to manage the condition.